The introduction of RF-ID systems as a potential replacement for the bar code, which is susceptible to faults and may be used only in direct visual contact with the scanner, or as a security feature on packaging and other goods is deemed to be a forward-looking application for extremely inexpensive electronics. On account of the flexibility and the large variation range of packaging materials, circuits on flexible substrates, which can be produced in large numbers in roll-to-roll methods, are particularly of interest. On account of the enormous price pressure of such applications, silicon-based circuits are typically suitable only for performance-driven special applications, but not for the mass market.
Alternative systems with integrated circuits based on organic field effect transistors (OFET) constitute a possible solution for this mass application sector of inexpensive electronics.
Semiconducting polymers or organic semiconductors offer the potential, on the other hand, that inexpensive printing techniques may be used for their patterning and application. The gate potential for controlling the transistors may be chosen to be smaller, and the thinner the gate dielectric may be fabricated.
For direct integration into the production process of a packaging, the substrate compatibility is of particular interest. If the packaging is composed of paper or similar materials containing cellulose fibers, the polymer electronics should be integrable directly onto this support material. However, paper generally has a very rough surface, so that its use as a substrate makes high requirements of the integration process.
Although the use of paper as a substrate for polymer electronics is proposed in EP 1 073 993 B1, a concrete realization method is not specified. It is also known that paper is suitable as a substrate for the production of electrochromic displays or electrochemical transistors, without production details being known.